Contrast-enhanced MR angiography of thoracic vascular malformations in a pediatric population.

(1)

AJR 2003; 181:861-866

Contrast-Enhanced MR Angiography

of Thoracic Vascular Malformations

in a Pediatric Population

Filipe Caseiro-Alves1,2, Paulo Gil-Agostinho1, Graça Ramalheiro3 and Pedro Gil-Agostinho1

1_{Imacentro, Clinica de Imagiologia Médica, Rua S.Teotónio, Lote 8, 5°}

Esq., 3000-377 Coimbra, Portugal.

2_{Faculdade de Medicina de Coimbra, Cadeira de Imagiologia, 3000-075}

Coimbra, Portugal.

3_{Paediatric Cardiology Department, Hospital Pediátrico de Coimbra, Av.}

Bissaia Barreto, 3000 Coimbra, Portugal.

Received December 5, 2002;accepted after revision January 28, 2003.

Address correspondence to F. Caseiro-Alves (fcalves@netcabo.pt ).

Introduction

Diagnostic gadolinium-enhanced MR angiography has been successfullyused in the past few years for a vast array of medical indications [1].With the new high-performance gradients that allow the use ofan ultrashort TR and TE, three-dimensional (3D) data sets cannow be acquired in a single breath-hold. Also, the new schemesfor k-space reconstruction, such as the centric or elliptic-centricmodes, ensure the most

useful phase of reduced blood T1-weightedrelaxation is easily captured, increasing the temporal

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS

QUICK SEARCH: [advanced] Go

Author: Keyword(s): Year: Vol: Page:

This Article

Figures Only Full Text (PDF)

Alert me when this article is cited Alert me if a correction is posted

Services

Email this article to a friend Similar articles in this journal Similar articles in PubMed

Alert me to new issues of the journal Download to citation manager

Citing Articles

Citing Articles via HighWire Citing Articles via Google Scholar

Google Scholar

Articles by Caseiro-Alves, F. Articles by Gil-Agostinho, P. Search for Related Content

PubMed PubMed Citation Articles by Caseiro-Alves, F. Articles by Gil-Agostinho, P. Social Bookmarking What's this? Hotlight (NEW!) What's Hotlight?

Pictorial Essay

Top Introduction Technique Clinical Results Aortic Arch Anomalies

Abnormalities of the Pulmonary... Abnormal Venous Connections Follow-Up for Corrected Vascular... References

(2)

resolution necessaryto image both arterial and venous structures [1, 2].

Performing contrast-enhanced MR angiography in pediatric patients, particularlyneonates, poses additional problems because examinations are typicallyconducted with the patient under general anesthesia in a non-breath-holdfashion. Previous reports have shown the feasibility of using contrast-enhancedMR angiography in a pediatric population to study several vascularthoracic and abdominal abnormalities, mainly of the arterialsystem [2-5]. In addition, the ability to study malformationsof the thoracic vasculature in neonates under general anesthesiaand during spontaneous breathing has been described (Caseiro-AlvesF et al., presented at the Radiological Society of North Americameeting, December 2000). Our imaging group is working closely witha national referral center for pediatric cardiology and hasalready performed more than 100 of these procedures. All patientswere examined with light anesthesia produced by inhalation ofsevoflurane (Ultane, Abbott Laboratories, Amadora, Portugal).To date, no cases of severe adverse effects have been registered,even when imaging 1-day-old neonates with complex cyanotic congenitalcardiopathy and blood oxygen saturation levels as low as 40-50%.

Technique

Images were generated in two magnetic fields (1 and 1.5 T) (SignaHorizon and Signa MRI EchoSpeed Plus, General Electric MedicalSystems, Milwaukee, WI). A 3D fast gradient-echo sequence wasperformed in the coronal plane using a nominal slice thicknessof 3.2 mm and a partition number selected depending on the anatomicarea to cover. The choice of imaging coil depended on the size ofthe patient; the head

transmitting-receiver coil was regularlyused in infants who weighed less than 9 kg. The 3D sequence was acquired in 18-20 sec. It was launched after a fixed delayof 15 sec after the manual injection of a double dose (0.2 mmol/kgof body weight) of IV ionic gadopentetate dimeglumine (Magnevist,Schering, Berlin), and the contrast-generating k-space central lineswere acquired during the first few seconds. The complete procedure includingadministration of anesthesia was concluded in approximately10-15 min. Interpolated reconstruction was regularly appliedto obtain a final number of slices multiplied by a factor of2 or 4 without any penalty in acquisition time.

The native coronal two-dimensional slices (typically 80-120images) were transferred to a diagnostic workstation (AdvantageWindows 4.0, General Electric Medical Systems) for 3D postprocessingusing maximum-intensity-projection and volume-rendering techniques.

Clinical Results

Corroborating the findings of previous reports that focused mainly on the arterial thoracic vessels [6-8], this pictorialessay shows the potential uses of contrast-enhanced MR angiography for the diagnosis of vascular thoracic malformations in boththe arterial and venous systems in pediatric patients. Theseuses make the technique a valuable diagnostic tool with thepotential to replace the more invasive digital subtraction angiography.

Top

Introduction

Technique

Clinical Results Aortic Arch Anomalies

Top

Introduction Technique

Clinical Results

Aortic Arch Anomalies

(3)

Aortic Arch Anomalies

Aortic Coarctation

Aortic coarctation (Figs. 1A, 1B, and 1C) is a narrowing ofthe aortic arch generally at the level of the ductus arteriosus.This anomaly can be diffuse, causing tubular hypoplasia of theaortic arch (the infantile type), or segmental (the adult type).

Top Introduction Technique Clinical Results

Aortic Arch Anomalies

View larger version

(96K):

[in this window] [in a new window] [as a PowerPoint slide]

Fig. 1A. —Spectrum of findings in selected cases of aortic coarctation

(arrowhead, A and B) shown on contrast-enhanced MR angiograms obtained using three-dimensional techniques. Parasagittal oblique

maximum-intensity-projection image of 2-day-old female neonate shows simple isolated coarctation at its typical location.

(78K):

Fig. 1B. —Spectrum of findings in selected cases of aortic coarctation

(arrowhead, A and B) shown on contrast-enhanced MR angiograms obtained using three-dimensional techniques. Maximum-intensity-projection image of 1-year-old male infant displays collaterals (intercostals) developed for arterial circulation.

Fig. 1C. —Spectrum of findings in selected cases of aortic

coarctation (arrowhead, A and B) shown on contrast-enhanced MR angiograms obtained using three-dimensional techniques. Posterior oblique volume-rendered image of 28-day-old male neonate shows

(4)

Aortic Arch Interruption

Aortic arch interruption (Fig. 2) is a complete separation ofthe ascending and descending segments of the thoracic aorta.According to Weinberg [8], aortic arch interruption can be classifiedas type A, when the interruption is distal to the left subclavianartery origin; type B, when between the carotid and left subclavian arteries;or type C, when located in the proximal aortic arch betweenthe carotid arteries.

Double Aortic Arch

Double aortic arch (Figs. 3A, and 3B) corresponds to the persistenceof both fetal aortic arches and has several variants: both arches maybe widely patent or one of the two arches may became hypoplasticor even atretic (usually the one on the left side). The tracheaand esophagus may be completely surrounded by the aortic arches,which results in a vascular ring. Because some degree of tracheomalaciais usually associated with this condition, clinical signs associatedwith vascular compression such as stridor or vomiting may bepresent.

(131K):

severe coarctation associated with hypoplastic distal aortic arch.

View larger version (127K): [in this window] [in a new window] [as a PowerPoint slide]

Fig. 2. —2-day-old male neonate with aortic arch interruption.

Contrast-enhanced three-dimensional MR angiogram obtained using volume-rendering technique reveals type A interruption of aortic arch (arrow). Arrowhead = left subclavian artery.

(5)

Aberrant Right Subclavian Artery

An aberrant right subclavian artery (Fig. 4) can give rise tothe clinical sign of dysphagia lusoria. In patients with thismalformation, the right subclavian artery (arteria lusoria)crosses the superior mediastinum behind the esophagus and potentiallycauses compression over its posterior wall.

(109K):

Fig. 3A. —Contrast-enhanced three-dimensional MR angiograms

reveal double aortic arch (arrows) that gave rise to stridor in 75-day-old male infant. Coronal oblique maximum-intensity-projection image shows early bifurcation of ascending aorta.

Fig. 3B. —Contrast-enhanced three-dimensional MR

angiograms reveal double aortic arch (arrows) that gave rise to stridor in 75-day-old male infant. Superior volume-rendered image shows double aortic arch.

Fig. 4. —Posterior contrast-enhanced three-dimensional MR

angiogram obtained using volume-rendering technique shows aberrant right subclavian artery (arrow) in 10-day-old male neonate.

(6)

Right Aortic Arch with Retroesophageal Kommerell Diverticulum

In patients with this malformation, the aortic arch has a right-sided configurationand the first emerging branch is the left carotid artery. A retroesophagealvessel of variable size (the so-called Kommerell diverticulum) givesrise to the left subclavian artery (Fig. 5). This abnormal pouch ofvariable length corresponds to the atretic portion of the leftfetal arch and is connected to the left ductus arteriosus or ligamentum arteriosum. This vessel arrangement may also behaveas a vascular ring that produces dysphagia.

Right Aortic Arch with Mirror Image of the Supraaortic Vessels

As the name implies, the vessels are arranged as a mirror imageof the left aortic arch (Figs. 6A, and 6B). This condition isone of the most common aortic arch abnormalities and is frequentlyassociated with other congenital cardiopathy.

(133K):

Fig. 5. —Posterior contrast-enhanced three-dimensional MR

angiogram obtained using volume-rendering technique shows incomplete double aortic arch forming retroesophageal

Kommerell diverticulum (arrowhead) in 35-day-old male infant. Left subclavian artery (arrow) can be seen arising in

(7)

Abnormalities of the Pulmonary Arteries

There is a broad spectrum of possible congenital malformations of the pulmonary trunk and major vessels, ranging from isolated stenosis to severe hypoplasia or even atresia. In addition to revealing the presence or absence of the major pulmonary trunk and branches, contrast-enhanced MR angiography allows the directmeasurement of the diameter of these pulmonary vessels (Fig. 7).These measurements are important in determining

whethera surgical shunt (e.g., Blalock-Taussig shunt) can be createdto correct the malformation because creating this shunt maynot be feasible if the pulmonary arteries measure less than3 mm.

(103K):

Fig. 6A. —Contrast-enhanced three-dimensional MR angiograms

obtained using volume-rendering technique show right aortic arch with mirror image of supraaortic vessels in 12-day-old female neonate with dextrocardia. Anterior (A) and posterior (B) images show right aortic arch with mirror image of supraaortic vessels and also reveal double superior vena cava: straight arrow points to left superior vena cava; arrowhead, to right superior vena cava; and curved arrow, to left brachiocephalic trunk.

(109K):

Fig. 6B. —Contrast-enhanced three-dimensional MR angiograms

obtained using volume-rendering technique show right aortic arch with mirror image of supraaortic vessels in 12-day-old female neonate with dextrocardia. Anterior (A) and posterior (B) images show right aortic arch with mirror image of supraaortic vessels and also reveal double superior vena cava: straight arrow points to left superior vena cava; arrowhead, to right superior vena cava; and curved arrow, to left brachiocephalic trunk.

Top

Introduction Technique Clinical Results Aortic Arch Anomalies

Abnormalities of the Pulmonary...

Abnormal Venous Connections Follow-Up for Corrected Vascular... References

(8)

Abnormal Venous Connections

Pulmonary

Abnormal pulmonary venous connections can be divided into partialabnormal venous return, such as that seen in patients with scimitarsyndrome (Fig. 8), and total abnormal venous return. The lattercategory can be further subdivided: the supracardiac type, inwhich a vertical vein draining the common pulmonary veins joinsthe left innominate vein to open into the superior

vena cava(Figs. 9A and 9B); the infracardiac type, in which the pulmonaryveins drain directly into the coronary sinus; the common type,in which the pulmonary veins drain into the right atrium; andthe rare infradiaphragmatic type, in which the pulmonary veinsjoin in a common trunk to drain into the portal vein (Fig. 9C).

(115K):

Fig. 7. —1-day-old male neonate with hypoplasia of pulmonary

artery branches. Contrast-enhanced three-dimensional MR angiogram obtained using volume-rendering technique allows diameter of vessel to be measured. Dotted line corresponds to diameter measurement of left pulmonary artery (2.6 mm). AA = ascending aorta, LA = left atrium, arrowhead = left pulmonary artery.

Top

Abnormalities of the Pulmonary...

Abnormal Venous Connections

Follow-Up for Corrected Vascular... References

Fig. 8. —3-year-old boy with partial abnormal pulmonary

venous return. Anterior contrast-enhanced three-dimensional MR angiogram obtained using maximum-intensity-projection technique reveals connection of right pulmonary vein to inferior vena cava (arrow), indicating scimitar syndrome.

(9)

Fig. 9A. —Two types of total abnormal pulmonary venous

return shown on contrast-enhanced three-dimensional MR angiography. Coronal image of 1-day-old male neonate reveals supracardiac type of total abnormal pulmonary venous return: common vertical vein (arrow) drains all pulmonary veins.

Fig. 9B. —Two types of total abnormal pulmonary venous

return shown on contrast-enhanced three-dimensional MR angiography. Volume-rendered image of same patient as shown in A reveals connection of pulmonary veins (arrowheads) to common vertical vein (arrow) better than A.

Fig. 9C. —Two types of total abnormal pulmonary venous return

shown on contrast-enhanced three-dimensional MR angiography. Coronal image of 3-day-old male neonate with infracardiac type of total abnormal venous return shows pulmonary veins converge toward single abnormal channel (arrowhead) that crosses mediastinum to drain into left portal vein (arrow).

(10)

Systemic

These conditions are variants of the normal systemic venousdrainage and do not produce clinical symptoms or signs. Themost common variant is a persistent left superior vena cavaconnecting either to the right atrium in 92% of cases (Figs.10A, and 10B) or to the left atrium in the remaining cases.The depiction of a persistent left superior vena cava may influencethe choice of the side on which to perform a surgical pulmonary-systemicshunt.

Follow-Up for Corrected Vascular Abnormalities

Contrast-enhanced MR angiography can also be useful for the

(89K):

Fig. 10A. —2-year-old boy with abnormal systemic venous connection

shown on contrast-enhanced three-dimensional MR angiography. Lateral maximum-intensity-projection image (A) and anterior volume-rendered image (B) show persistent left superior vena cava (arrow) connects to coronary sinus (arrowhead, A).

Fig. 10B. —2-year-old boy with abnormal systemic venous

connection shown on contrast-enhanced three-dimensional MR angiography. Lateral maximum-intensity-projection image (A) and anterior volume-rendered image (B) show persistent left superior vena cava (arrow) connects to coronary sinus (arrowhead, A).

(11)

evaluation of patients who have undergone surgery to correcta vascular abnormality. Although surgically created shunts are small, contrast-enhanced MR angiography can reveal whether theshunt is patent, as we have observed in patients with Blalock-Taussigshunts (Figs. 11A, and 11B). In addition, the postsurgical statusof a surgically corrected aortic coarctation can be monitoredby obtaining direct measurements of the vessel diameter (Fig. 12). Introduction Technique Clinical Results Aortic Arch Anomalies

Abnormalities of the Pulmonary... Abnormal Venous Connections

Follow-Up for Corrected Vascular...

References

Fig. 11A. —Contrast-enhanced MR angiograms obtained at

postsurgical follow-up of 3-year-old girl who underwent placement of modified Blalock-Taussig shunt. Posterior volume-rendered image (A) and coronal maximum-intensity-projection image (B) show patency of modified Blalock-Taussig shunt (arrow).

Fig. 11B. —Contrast-enhanced MR angiograms obtained at

postsurgical follow-up of 3-year-old girl who underwent placement of modified Blalock-Taussig shunt. Posterior volume-rendered image (A) and coronal maximum-intensity-projection image (B) show patency of modified Blalock-Taussig shunt (arrow).

Fig. 12. —4-year-old boy in whom recoarctation of aorta was

suspected on basis of findings on Doppler sonograms (not shown) that revealed 15-mm-Hg systolic pressure gradient between two segments of aorta. This posterior oblique contrast-enhanced MR angiogram obtained using volume-rendering technique was used to calculate aortic diameter.

(12)

References

1. Joarder R, Gedroye WM. Magnetic resonance an giography: the state of the art. Eur Radiol2001; 11:446 -453[Medline]

2. Holmqvist C, Larsson E-M, Stahlberg F, Laurin S. Contrast-enhanced thoracic 3D-MR angiography in infants and children. Acta Radiol 2001;42:50 -58

[Medline]

3. Lam WW, Chan JH, Hui Y, Chan F. Non-breathhold gadolinium-enhanced MR angiography of the thoracoabdominal aorta: experience in 18 children. AJR 1998;170:478 -480[Free Full Text] 4. Teo EL, Strouse PJ, Prince MR. Applications of magnetic resonance imaging and magnetic reso

nance angiography to evaluate the hepatic vasculature in the pediatric patient. Pediatr Radiol1999; 29:238 -243[Medline]

5. Neimatallah MA, Ho VB, Dong Q, et al. Gadolin ium-enhanced 3D magnetic resonance angiogra phy of the thoracic vessels. J Magn Reson Imaging 1999;10:758 -770[Medline]

6. Krinsky GA, Reuss PM, Lee VS, Carbognin G, Rofsky NM. Thoracic aorta: comparison of sin gle-dose breath-hold and double-dose non-breathhold gadolinium-enhanced three-dimensional MR angiography. AJR 1999;173:145 -150[Abstract/Free Full Text]

7. Krinsky G. Gadolinium-enhanced three-dimensional magnetic resonance angiography of the thoracic aorta and arch vessels. Invest Radiol 1998;33:587 -605[Medline]

8. Weinberg PM. Interrupted aortic arch. In: Moss AJ, Adams FH, Emmanouilides GC, eds. Moss and Ad ams' heart disease in infants, children, and adoles cents: including the fetus and young adult, 5th ed. Philadelphia: Williams & Wilkins, 1995:828 -832

CiteULike Complore Connotea Delicious Digg Reddit Technorati What's this?

This article has been cited by other articles:

(107K):

Top

Abnormalities of the Pulmonary... Abnormal Venous Connections Follow-Up for Corrected Vascular...

(13)

S.-F. Ko, C.-D. Liang, C.-C. Huang, S.-H. Ng, M.-J. Hsieh, J.-P. Chang, and M.-C. Chen

Clinical feasibility of free-breathing, gadolinium-enhanced magnetic resonance angiography for assessing extracardiac thoracic vascular abnormalities in young children with congenital heart diseases.

J. Thorac. Cardiovasc. Surg., November 1, 2006; 132(5): 1092 - 1098. [Abstract][Full Text][PDF]

This Article

Figures Only Full Text (PDF)

Alert me when this article is cited Alert me if a correction is posted

Services

Email this article to a friend Similar articles in this journal Similar articles in PubMed

Alert me to new issues of the journal Download to citation manager

Citing Articles

Citing Articles via HighWire Citing Articles via Google Scholar

Google Scholar

Articles by Caseiro-Alves, F. Articles by Gil-Agostinho, P. Search for Related Content

PubMed PubMed Citation Articles by Caseiro-Alves, F. Articles by Gil-Agostinho, P. Social Bookmarking What's this? Hotlight (NEW!) What's Hotlight?